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‘Too little’ oil for global warming

By Andy Coghlan

Oil and gas will run out too fast for doomsday global warming scenarios to materialise, according to a controversial analysis presented this week at the University of Uppsala in Sweden. The authors warn that all the fuel will be burnt before there is enough carbon dioxide in the atmosphere to realise predictions of melting ice caps and searing temperatures.

Defending their predictions, scientists from the Intergovernmental Panel on Climate Change say they considered a range of estimates of oil and gas reserves, and point out that coal-burning could easily make up the shortfall. But all agree that burning coal would be even worse for the planet.

The IPCC’s predictions of global meltdown provided the impetus for the 1997 Kyoto Protocol, an agreement obliging signatory nations to cut CO2 emissions. The IPCC considered a range of future scenarios, from profligate burning of fossil-fuels to a fast transition towards greener energy sources.

Energy discrepancy

But geologists Anders Sivertsson, Kjell Aleklett and Colin Campbell of Uppsala University say there is not enough oil and gas left for even the most conservative of the 40 IPCC scenarios to come to pass (see graphic).

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Billions of barrels

Although estimates of oil and gas reserves vary widely, the researchers are part of a growing group of experts who believe that oil supplies will peak as soon as 2010, and gas soon after (New Scientist print edition, 2 August 2003).

Their analysis suggests that oil and gas reserves combined amount to the equivalent of about 3500 billion barrels of oil ­ considerably less than the 5000 billion barrels estimated in the most optimistic model envisaged by the IPCC.

The worst-case scenario sees 18,000 billion barrels of oil and gas being burnt ­ five times the amount the researchers believe is left. “That’s completely unrealistic,” says Aleklett. Even the average forecast of about 8000 billion barrels is more than twice the Swedish estimate of the world’s remaining reserves.

Nebojsa Nakicenovic, an energy economist at the University of Vienna, Austria who headed the 80-strong IPCC team that produced the forecasts, says the panel’s work still stands. He says they factored in a much broader and internationally accepted range of oil and gas estimates than the “conservative” Swedes.

Even if oil and gas run out, “there’s a huge amount of coal underground that could be exploited”, he says. Aleklett agrees that burning coal could make the IPCC scenarios come true, but points out that such a switch would be disastrous.

Coal is dirtier than oil or gas and produces more CO2 for each unit of energy, as well as releasing large amounts of particulates. He says the latest analysis is a “shot across the bows” for policy makers.